EasyBound is a powerful tool for performing curve fitting of data obtained from receptor binding experiments. It utilizes iterative non-linear regression to analyze the data. During the last decades the use of nonlinear regression analysis has become more and more widespread for the evaluation of experimental effects in pharmacological studies (Motulsky and Ransnas, 1987).

In practical pharmacological use, nonlinear regression has become identical to curve fitting of experimental data typically from receptor binding studies. Nonlinear regression has the major advantage that it allows analysis of the original raw data as opposed to e. g. logarithmic transformations required in order to perform linear regression of the data. The drawback is that nonlinear regression involves complex iterative mathematical calculations in order to fit the data to the assumed nonlinear equation. Hence, in order to be used in a practical manner it requires a computer for the analysis. With EasyBound non-linear regression becomes easily available for all users.

EasyBound works as a custom application under Microsoft Excel. Thereby EasyBound incorporates the power of non-linear regression with the ease-of-use of a modern spreadsheet program and the ability of the spreadsheets to handle large amounts of data.

Furthermore, EasyBound has been developed to be user friendly and to efficiently calculate large amounts of data as automatically as possible.

EasyBound fully implements the Gauss-Newton algorithm as modified by Levenberg (Levenberg, 1944) and Marquardt (Marquardt, 1963) for the non-linear regression analysis. This is the most powerful and most frequently used algorithm.